Alprazolam and diazepam, the two most prescribed benzodiazepine anxiolytics in the United States, have potential for addictive use. The Drug Abuse Warning Network (DAWN) indicates they are the most mentioned benzodiazepines, and the National Household Survey indicates significant abuse of tranquilizers. Both drugs are rapidly absorbed and enter the brain tissue rapidly, leading to reinforcement. Alprazolam has a shorter half-life, which may lead to more withdrawal symptoms than diazepam. In experimental conditions, they are among the most reinforcing benzodiazepines. Each causes a withdrawal syndrome, but alprazolam withdrawal may be more severe and may occur after a shorter period of use. Adverse effects from their use are said to be rare, yet subtle negative consequences may be seen with some regularity. Alprazolam deserves special caution because of its relative newness, great popularity, reinforcing capabilities, relatively severe withdrawal syndrome, and reports of addiction and negative consequences of use.